فهرست مطالب eslam majidi

To evaluate the effect of drought stress on grain yield, yield component, morphologic and phonological traits on 30 genotypes of wheat, an experiment in the form randomized complete block with three replication at 2 levels of irrigation (normal and stress), was carried out. Results showed that the studied genotypes were significantly different in terms of grain yield, 100-seed weight, number of seeds per pod, number of pods per plant, day to maturity, and seed size under stress and non-stress conditions. According to the results, it can be seen that Kavir, Pishtaz and Helmand cultivars showed the lowest yield reduction and Navid, Karim and Alvand cultivars showed the highest grain yield decrease among all cultivars. The analysis of tolerance index correlation showed index of tolerance stress, using mean and using numeral mean are the best indexes for identifying genotype with high yield in this test According to the results of phenotypic correlations, stepwise regression, path analysis and principal component analysis in both normal and stress conditions, it can be concluded that, expected that the traits of number of spike in plant, total spikes weight, biological yield, main spike of weight, were most important and effective traits affecting yield and considering that among the genotypes, The highest diversity was observed for these traits, therefore selecting and breeding for these traits can ideally be improved the yield Genotype grouping in both conditions was conducted based on studied traits with UPGMA method, in both conditions investigated genotypes were grouped in five clusters.

Drought is one of the most important factors limiting corn production in the world. On the other hand, the use of renewable resources and inputs such as vermicompost is one of the principles of sustainable agriculture. Therefore, in order to investigate the effect of deficit irrigation, chemical fertilizers and vermicompost an experiment has been performed in the form of split split plots in a randomized complete block design with 3 replications for two years (2017 and 2018) in Kermanshah Agricultural Research and Training Center. Irrigation treatment include optimum, 80% and 60% of water requirement. Chemical fertilizer include 100% and 50% recommended and vermicompost include 0, 2, 4,and 6 ton ha-1 arranged as main plots, sub plots, and sub sub plots, respectively. Results show that leaf area index is decreased from 4.51 to 1.6 from normal irrigation to intense drought stress. The highest yield of fresh forage (82.5 ton ha-1) is obtained in optimal irrigation treatment and combined use of 100% chemical fertilizer and 6 ton ha-1 of vermicompost and the lowest rate (30.1 ton ha-1) is related to 60% water requirement and no use of vermicompost chemical fertilizers. At all irrigation tratments, the percentages of forage protein increase with the use of fertilizers and vermicompost, and the highest percentage of forage protein (10.2%) is obtained in complete irrigation treatment and 100% fertilizer application and 6 ton ha-1 vermicompost. Based on the results in irrigation treatment by 60% of water requirement and application of 50% of chemical fertilizer, application of vermicompost at the rate of six tons per hectare, compared to no application, increases fresh forage by 26.26% and protein by 6.9%.

Wheat is a major crop among cereals and plays a critical role in the national economy of developing countries. In Iran, grain yield of wheat reduced by terminal drought stress. Drought stress is one of the most important factors limiting the growth and yield of crops such as wheat as the most important crop in arid and semi-arid regions of the world as well as in Iran. It is growing in a wide range of climatic conditions and plays an important role in Supplying human food needs. This plant is exposed to drought stress at the germination stage and the end of the growth season. Genotypes that can react to drought stress at the germination stage have a better growth in seedlings. The aims of this research is to Investigate the response of the germination components to different levels of drought stress in bread wheat genotypes and also finding drought tolerant genotypes.

This research was conducted to study of drought stress treatments on seed characteristics and seedling growth of wheat Thirty wheat genotypes including Mihan, Aroom, Navid, Alvand, Zarrin, Zare, Sison, Alamoot, Gascogen, Heydari, Rizhav, Baran, Karim, Koohdasht, Pishgam, Star, Pishtaz, Qods, Marvdasht, Sardari, Kavir, Dez, Virinak, Alborz, Hirmand, Roshan, Zagros, Bezostaya, Azar and Sirvan. For this propose, a factorial experiment was conducted using 4 levels of osmotic potential (0, -4, -8, -12, -16 bar) using poly ethylene glycol. Seeds were sown on laboratory and data were recorded and analyzed for percent and speed of germination, length of root and shoot, vigor index and fresh and dry weight of seedling. Data analysis was carried out using SAS (Statistical Analysis System ver 9.1), MSTAT-C, SPSS 18 and means were compared using by Duncan's multiple range tests (P< 0.05).

In agreement with other studies, drought stress condition significantly decreased All Germination traits with increasing levels of stress. The results showed significant differences among genotypes, drought stresses and genotypes × drought stress interaction for most of traits. In this study, 30 wheat genotypes were exposed to drought stress at flowering stage. The genotype Heidari had higher performance for length of root and percent and speed of germination whereas Azar genotype was the worse. Genotype Sardari had higher performance for seedling vigor index and length of shoot whereas Azar genotype was the worse. Genotype Roshan had higher performance for fresh and dry weight of seedling, while Alvand genotype was the worse. The results in control condition was showed that length of root had the highest positive and significant correlation with percent and speed of germination and germination index and under drought stress condition between all of traits were positive and significant correlation. According to principal component analysis, two main components were selected that in total 72 percent of the total variation was explained.Factors analysis was performed using the studied traits, and two factors( based on specific values larger than one) justify about 72% of the variations in the total data, of which the first factor justifies about 53% of the variations, including traits Root length, stem length, percentage and speed of germination, seed index and germination index, and the second factor, which justifies about 19% of the variation, includes somewhat two traits and seedling dry and fresh weight. Therefore, selection based on these two factors showed the most effect on germination of seeds. In order to determine the variation between different genotypes of different types and determine the relationship between genotypes, cluster analysis using Ward method was performed based on 8 indicators and component of the study. Genetic types of wheat were grouped in 4 clusters with similar intra-group characteristics and non-similar groups. It indicated that 9 genotypes in the first cluster, 14 genotypes in the second cluster, 6 genotypes in the third cluster and Karim genotype were placed alone in the fourth cluster. Information contained in each cluster Groups have led to the identification of genotypes with unique traits and will help us select parental cross-breeds.The fourth cluster (including Karim genotype) had the highest mean and deviation from the mean for root length, percentage and speed of germination, seedling fresh weight and germination index. The third cluster included six genotypes such as Rijaw, Starr, Ghods, Marvdasht, Sardari And bright in terms of stem length, vigor index and seedling dry weight had the highest mean. It can also be argued that the Karim and Heidari genotypes can be used for cross-breeding programs in two separate clusters and maximum genetic distance between them.

In order to identify yield and yield component QTLs under control and salt-stress conditions, a population of 254 recombinant inbred lines (RILs), derived from a cross between two bread wheat cultivars, (Roshan / Sabalan), was assessed. Parents and their 254 recombinant inbred lines (RILs) were evaluated in an alpha-lattice design with two replications in two control and saline environments of Yazd in 2011-2012 cropping season. Yield and yield-related traits were evaluated at harvest time. The genotyping was carried out using SSR and DArT markers. A, B and D genomes were covered by 411.8, 620.4 and 67.5 cM, respectively. Also, a total of 48 QTLs were detected on 11 chromosomes for grain yield, biological yield, harvest index, thousand-kernel weight, grain number per spike, spike weight and spikelet number per spike. Roshan (salt tolerance) alleles were associated with an increase yield under saline conditions. SSR markers including gwm146, gwm577, gwm249 (on chromosomes 2A and 7B) were tightly associated with different QTLs. The major effect QTLs were located on chromosomes 1A and 7B for grain yield, harvest index and spike weight, which were explained 10.2%, 12.98% and 29 % of the total phenotypic variance, respectively. These QTLs and markers could be suitable for marker-assisted selection and gene stacking techniques. Moreover, co-located QTLs were detected on chromosome 2B for evaluated traits.